A system dealing with data on a large scale like a system in a data center manages data by using host computers and storage apparatuses. A storage apparatus has hard disk drives arranged in an array and manages the plurality of hard disk drives according to the RAID, thereby protecting the data.
Regarding conventional storage apparatuses, the number of hard disk drives mounted in a storage apparatus has been increasing in association with an increase in the amount of data to be handled by the storage apparatus. For example, a conventional storage apparatus has a plurality of hard disk drives mounted in a dedicated chassis (see Patent Literature 1).
In this type of storage apparatus, the air supplied from outside the chassis into the chassis is made to flow through flow paths formed in the chassis to cool the hard disk drives and then the air is discharged from a fan unit on the top surface of the chassis.
On the other hand, there is another type of storage apparatus in which a user sequentially adds modulars equipped with hard disk drives not to a dedicated chassis, but to a general purpose chassis (see Patent Literature 2).
In the conventional storage apparatus which uses the general purpose chassis, exhaust fans cannot be provided on the top surface of the chassis and air flow paths cannot be formed inside the chassis. Therefore, the conventional storage apparatus is configured so that a modular in which a power source and fans are integrated with hard disk drives is placed in the chassis. Such a modular is inserted from the front side of a rack into the chassis. Cooling air is introduced through the front face of a module into the rack and then discharged from the back face of the module.